How to randomly place ones in specified postions of a matrix?

I have a matrix.

A=[ 0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0];

I have to randomly place specific number of ones say 8 or 10 in bold zeros positions.

Bold postions may change. Another problem is if i pick 10 positions in this matrix randomly. How to randomly place say 5 ones at those randomly selected 10 positions?

How to do this?

Answer 1

[Andrei Bobrov]

1.

k = 10;
[m,n] = size(A);
[i1,j1] = ndgrid(1:m,1:2);
[i2,j2] = ndgrid(1:3,3:n);
ii = sub2ind([m,n], [i1(:);i2(:)],[j1(:);j2(:)]);

A(ii(randperm(numel(ii),k))) = 1;

2.

K = 10;
L = 5;
ii = randperm(numel(A),K);
A(ii(randperm(K,L))) = 1;

[Muhammad Nabeel Hussain]

Thankyou sir